JP3726290B2 - Active vibration control actuator - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an active vibration damping actuator that attenuates vibration of a vibrating body by the magnetic force of an electromagnet.
[0002]
[Prior art]
An example of this type of actuator is a voice coil motor (linear motor). The voice coil motor is connected to a vibrating body via a rod, and pushes and pulls the vibrating body according to the vibration of the vibrating body, thereby attenuating the vibration of the vibrating body. Since the thrust of the voice coil motor is proportional to the current, there is an advantage that high-precision control can be easily performed.
[0003]
[Problems to be solved by the invention]
However, since the thrust of the voice coil motor acts only in one direction, only one direction of vibration can be controlled by one voice coil motor. Therefore, when controlling the vibrations in the three directions of height and width, there is a problem that the number of voice coil motors increases, the apparatus becomes complicated, and the cost becomes high.
[0004]
Therefore, an object of the present invention is to provide an active vibration damping actuator that can control vibrations in a plurality of directions together.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention arranges an electromagnet and a magnetic body close to each other, and changes the magnetic force of the electromagnet according to the vibration generated between the electromagnet and the magnetic body. In an active vibration damping actuator that attenuates vibrations, a non-magnetic conductive plate through which a magnetic field line of an electromagnet penetrates substantially vertically is disposed on the magnetic body.
[0006]
The apparatus further comprises vibration detecting means for detecting vibration generated between the electromagnet and the magnetic body in a direction substantially perpendicular to the magnetic field lines of the electromagnet, and bias means for causing a bias current to flow through the electromagnet. The bias current is changed according to the vibration detected by the means.
[0007]
[Action]
In the active vibration damping actuator of the present invention, a non-magnetic conductive plate through which the magnetic field lines of the electromagnet penetrate substantially vertically is disposed on the magnetic material. For this reason, when the vibration generated between the electromagnet and the magnetic material is attenuated, the magnetic lines of force of the electromagnet penetrate through the non-magnetic conductive plate, and an eddy current is generated in the conductive plate. Thereby, a resistance force (Lorentz force) is generated between the electromagnet and the conductive plate. This resistance force is generated in a direction orthogonal to the magnetic field lines of the electromagnet, and suppresses vibration between the electromagnet and the magnetic material generated in the same direction. That is, by changing the magnetic force of the electromagnet, not only the vibration generated between the electromagnet and the magnetic material is attenuated, but also the electromagnet generated in the direction perpendicular to the magnetic field lines of the electromagnet due to the resistance force between the electromagnet and the conductive plate. And the vibration between the magnetic material is attenuated. Here, since the vibration is attenuated by the magnetic force of the electromagnet, the direction of the former vibration coincides with the direction of the magnetic field lines of the electromagnet and is different from the latter. Therefore, both vibrations in a plurality of directions are controlled together.
[0008]
In addition, the active vibration damping actuator further includes vibration detection means and bias means, and the bias means changes the bias current flowing through the electromagnet according to the vibration detected by the vibration detection means. Here, the vibration detected by the vibration detection means is generated in a direction substantially orthogonal to the magnetic field lines of the electromagnet, and the bias current of the electromagnet is increased or decreased according to this vibration. Therefore, according to this vibration, the number of lines of magnetic force of the electromagnet penetrating the conductive plate is increased or decreased, and the resistance force between the electromagnet and the conductive plate is increased or decreased, thereby enabling quick attenuation of the vibration.
[0009]
【Example】
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0010]
FIG. 1 shows an embodiment of an active vibration damping actuator according to the present invention. The mechanism portion of the active vibration damping actuator includes a pair of electromagnets 1 and 2 disposed above and below and a magnetic body 3 disposed between the electromagnets 1 and 2. Further, the non-magnetic conductive plates 4 and 5 are fixed.
[0011]
FIG. 2 shows the mechanism of the actuator as viewed from the side, and FIG. 3 shows the mechanism of the actuator as viewed from above. As shown in these drawings, an electromagnet support column 6 protrudes and a pair of electromagnets 1 and 2 are fixed to the electromagnet support column 6. Similarly, a magnetic support pillar 7 is provided in a protruding manner, and the magnetic body 3 is fixed to the magnetic support pillar 7.
[0012]
This active vibration damping actuator is applied to a vibration isolation table as shown in FIGS. In this vibration isolator, the air springs 12 are disposed at four locations on the base 11, and the vibration insulating plate 13 is placed on the air springs 12.
[0013]
Similarly to these air springs 12, the electromagnet support columns 6 protrude from four positions of the base 11, and the electromagnet support columns 6 support the pair of electromagnets 1 and 2. In addition, the support pillars 6 for magnetic bodies are provided to project at four locations on the lower surface of the vibration insulating plate 13, and the magnetic bodies 3 are supported by the support pillars 7 for magnetic bodies.
[0014]
Here, when the vibration insulating plate 13 vibrates, each magnetic body 3 also vibrates accordingly. At this time, if the magnetic force of the pair of electromagnets 1 and 2 is adjusted so that the vibration of the magnetic body 3 is attenuated for each magnetic body 3, the vibration of the vibration insulating plate 13 can be attenuated.
[0015]
The control for attenuating this vibration will be described next. For simplification of explanation, FIG. 1 shows a pair of electromagnets 1 and 2 and one magnetic body 3.
[0016]
In FIG. 1, a z-direction acceleration detector 14 and a z-direction displacement detector 15 are fixed to the magnetic support column 7. The z-direction acceleration detector 14 detects the acceleration in the z direction (height direction) of the magnetic body 3 due to the vibration of the vibration insulating plate 13 and applies the detection signal Z _g to the integration circuit 16. The integrating circuit 16 integrates the detection signal Z _g indicating acceleration to form a signal Z _v1 indicating the velocity in the z direction, and _applies this signal Z _v1 to the adder 18 via the gain adjusting amplifier 17.
[0017]
z direction displacement detector 15, the gap l of the displacement detector 15 and the magnetic body 3, i.e. to detect the position in the z direction of the magnetic body 3, and outputs a detection signal Z _l. This detection signal Z _l is applied to the adder 18 via the gain adjustment amplifier 19 and also to the differentiation circuit 20.
[0018]
The differentiating circuit 20 differentiates the detection signal Z _l indicating the position to form a signal Z _v2 indicating the velocity in the z direction, and _applies this signal Z _v2 to the adder 18 via the gain adjusting amplifier 21.
[0019]
Therefore, the adder 18 has a signal Z _v1 indicating the speed obtained by integrating the acceleration in the z direction, a signal Z _l indicating the position in the z direction, and a speed obtained by differentiating the position in the z direction. The indicated signal Z _v2 is applied. The adder 18 adds the signal Z _v1 , the signal Z _l , and the signal Z _v2 and outputs a signal (Z _v1 + Z _l + Z _v2 ) indicating the sum. This signal (Z _v1 + Z ₁ + Z _v2 ) is applied to the adder 22, inverted by the inverting circuit 23, and then added to the adder 24.
[0020]
On the other hand, an x-direction acceleration detector 25 is fixed to the magnetic support pillar 7. The x-direction acceleration detector 25 detects the x-direction acceleration of the magnetic body 3 accompanying the vibration of the vibration insulating plate 13, that is, the lateral acceleration, and applies the detection signal X _g to the integral absolute value circuit 26. Integrating the absolute value circuit 26 integrates the detection signal X _g representing the acceleration, the absolute value of the x-direction velocity signal indicating the absolute value of the speed | is formed and the signal | | X _v X _v | Is added to the adder 28 via the bias adjustment amplifier 27. The adder 28 adds the signal | X _v | and a preset bias voltage V _b, and adds a signal (V _b + | X _v |) indicating the sum of these to the adders 22 and 24.
[0021]
The adder 22 adds the signal (Z _v1 + Z _l + Z _v2 ) and the signal (V _b + | X _v |), and a signal indicating the sum (Z _v1 + Z _l + Z _v2 ) + (V _b + | X _v | is output. This signal (Z _v1 + Z ₁ + Z _v2 ) + (V _b + | X _v |) is applied to the power amplifier 29, where it is amplified and applied to the lower electromagnet 2. Further, the adder 24 adds the signal − (Z _v1 + Z _l + Z _v2 ) and the signal (V _b + | X _v |), and a signal − (Z _v1 + Z _l + Z _v2 ) + (V _b + | X _v |) is output. This signal − (Z _v1 + Z ₁ + Z _v2 ) + (V _b + | X _v |) is applied to the power amplifier 30, where it is amplified and applied to the upper electromagnet 1.
[0022]
For example, if the vibration insulating plate 13 is completely stationary, the acceleration detected by the z-direction acceleration detector 14 and the acceleration detected by the x-direction acceleration detector 25 are “0”. The speeds indicated by Z _v1 , Z _v2 , and | X _v | are also “0”, and only the signal Z _l from the z-direction displacement detector 15 and the bias voltage V _b remain. For this reason, a signal (Z ₁ + V _b ) is applied to the pair of electromagnets 1 and 2 via the power amplifiers 29 and 30. In this case, the same level of bias current flows through each of the electromagnets 1 and 2, and these electromagnets 1 and 2 generate the same magnetic force. As a result, the magnetic body 3 is held approximately at the center of the electromagnets 1 and 2 by the magnetic force of the electromagnets 1 and 2.
[0023]
At this time, the magnetic lines of force between the electromagnets 1 and 2 penetrate the conductive plates 4 and 5 of the magnetic body 3 substantially vertically. Thereby, an eddy current is generated in each of the conductive plates 4, 5, and a resistance force (Lorentz force) is generated between each of the conductive plates 4, 5 and each of the electromagnets 1, 2. Since this resistance force is generated in a direction substantially perpendicular to the lines of magnetic force between the electromagnets 1 and 2, displacement of the magnetic body 3 in the x direction is suppressed.
[0024]
Here, since the magnetic body 3 is located between the electromagnets 1 and 2, many lines of magnetic force are easily generated between the electromagnets 1 and 2. For this reason, a large eddy current is generated in each of the conductive plates 4, 5, and a sufficient resistance force is generated between each of the conductive plates 4, 5 and each of the electromagnets 1, 2. Therefore, this resistance force is effective for suppressing the displacement of the magnetic body 3 and is sufficiently useful for damping the vibration of the vibration insulating plate 13.
[0025]
Next, if vibration is generated in the vibration insulating plate 13 and the amplitude of this vibration is in the x direction, the acceleration is detected by the x direction acceleration detector 25, and the signal | X _v | is output from the integral absolute value circuit 26. , A signal (Z ₁ + V _b + | X _v |) is applied to the electromagnets 1 and 2 via the power amplifiers 29 and 30.
[0026]
Therefore, when vibration in the x direction occurs in the vibration insulating plate 13, the currents of the electromagnets 1 and 2 increase, and the number of magnetic lines passing through the conductive plates 4 and 5 increases. The resistance force between the electromagnets 1 and 2 is increased. Thereby, the vibration in the x direction of the vibration insulating plate 13 is quickly attenuated.
[0027]
Next, if vibration in the z direction is generated in the vibration insulating plate 13, acceleration is detected by the z direction acceleration detector 14, and a position is detected by the z direction displacement detector 15. For this reason, the signal Z _v1 from the integrating circuit 16, the signal Z _l from the z-direction displacement detector 15, and the signal Z _v2 from the differentiating circuit 20 are added to the adder 18, where the signal (Z _v1 + Z _l + Z _v2 ).
[0028]
At this time, if the vibration in the vibration insulating plate 13 does not include a component in the x direction and the speed indicated by the signal | X _v | is “0”, the adder 22 determines that the signal (Z _v1 + Z _l + Z _v2 ) , The signal V _b is added, and a signal (Z _v1 + Z _l + Z _v2 ) + V _b indicating this sum is output. This signal (Z _v1 + Z _l + Z _v2 ) + V _b is applied to the lower electromagnet 2 via the power amplifier 29. The adder 24 adds the signal − (Z _v1 + Z _l + Z _v2 ) and the signal V _b and outputs a signal − (Z _v1 + Z _l + Z _v2 ) + V _b indicating the sum. This signal − (Z _v1 + Z _l + Z _v2 ) + V _b is applied to the upper electromagnet 1 via the power amplifier 30.
[0029]
Here, for example, if the magnetic body 3 is displaced upward due to the vibration of the vibration insulating plate 13, the signal (Z _v1 + Z _l + Z _v2 ) + V _{b of} the power amplifier 29 is increased, and the magnetic force of the lower electromagnet 2 is increased. Becomes larger. Further, the signal − (Z _v1 + Z _l + Z _v2 ) + V _{b of} the power amplifier 30 is reduced, and the magnetic force of the upper electromagnet 1 is reduced. That is, when the magnetic body 3 is displaced upward, the magnetic force of the lower electromagnet 2 is increased, and the magnetic force of the upper electromagnet 1 is decreased, whereby the magnetic body 3 is pulled back downward.
[0030]
On the other hand, if the magnetic body 3 is displaced downward, the signal (Z _v1 + Z _l + Z _v2 ) + V _{b of} the power amplifier 29 becomes small, and the magnetic force of the lower electromagnet 2 becomes small. Further, the signal − (Z _v1 + Z _l + Z _v2 ) + V _{b of} the power amplifier 30 increases, and the magnetic force of the upper electromagnet 1 increases. Thereby, the magnetic body 3 is pulled back upward.
[0031]
In other words, when vibration in the z direction occurs in the vibration insulating plate 13, a deviation occurs in the magnetic force of each of the electromagnets 1 and 2, and the magnetic body 3 is returned to the original position, thereby the z direction of the vibration insulating plate 13 The vibration of is quickly attenuated.
[0032]
If the vibration of the vibration insulating plate 13 includes both the x-direction component and the z-direction component, the signal (Z _v1 + Z _l + Z _v2 ) + (V _b + | X _v | ) And a signal − (Z _v1 + Z _l + Z _v2 ) + (V _b + | X _v |) are output from the power amplifier 30, whereby both vibrations in the x and z directions are attenuated.
[0033]
By the way, when the vibration insulating plate 13 is stationary, a bias current corresponding to the signal (Z ₁ + V _b ) flows through the electromagnets 1 and 2 as described above. When the vibration insulating plate 13 vibrates in the z direction, the currents of these electromagnets 1 and 2 are increased or decreased. Therefore, the magnetic force of the electromagnets 1 and 2 is increased or decreased with reference to the magnetic force of the electromagnets 1 and 2 when the bias current is flowing. This bias current is most preferably set to approximately ½ of the maximum allowable current of the electromagnets 1 and 2. This is because, when the currents of the electromagnets 1 and 2 are close to about ½ of the maximum allowable current, the proportional relationship between the current and the magnetic force is maintained, so that the vibration attenuation control can be performed stably.
[0034]
Further, the resistance force generated in the direction substantially orthogonal to the magnetic field lines between the electromagnets 1 and 2 suppresses not only the displacement of the magnetic body 3 in the x direction but also the displacement in the y direction (shown in FIG. 3). Therefore, similarly to the vibration in the x direction, the acceleration in the y direction of the magnetic body 3 is detected, and the current of each of the electromagnets 1 and 2 is increased according to the acceleration in the y direction to increase the resistance force. Also good. As a result, vibration damping control can be performed in the three directions xyz.
[0035]
The structure of the electromagnet, the material of the magnetic body, the material of the conductive plate, etc. can be selected as appropriate. Further, the configuration of the control system from the detection of vibration until the current is passed through the electromagnet can be variously modified.
[0036]
【effect】
As described above, in the active vibration damping actuator according to the present invention, the non-magnetic conductive plate through which the magnetic field lines of the electromagnet penetrate substantially perpendicularly is disposed on the magnetic material, so an eddy current is generated in the conductive plate. Thus, a resistance force is generated in a direction perpendicular to the magnetic field lines of the electromagnet. For this reason, by changing the magnetic force of the electromagnet, not only the vibration generated between the electromagnet and the magnetic body can be attenuated, but also the electromagnet generated in the direction perpendicular to the magnetic field lines of the electromagnet due to the resistance force between the electromagnet and the conductive plate. Can attenuate the vibration between the magnet and the magnetic material. That is, it is possible to control each vibration in a plurality of directions together.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of an active vibration damping actuator according to the present invention. FIG. 2 is a side view showing a mechanism portion of the actuator of this embodiment. FIG. 3 is a mechanism portion of the actuator of this embodiment. FIG. 4 is a side view showing a vibration isolation table to which the actuator of this embodiment is applied. FIG. 5 is a front view of the vibration isolation table to which the actuator of this embodiment is applied.
DESCRIPTION OF SYMBOLS 1, 2 Electromagnet 3 Magnetic body 4, 5 Conductive plate 6 Electromagnet support pillar 7 Magnetic support pillar 14 z direction acceleration detector 15 z direction displacement detector 16 Integration circuit 18, 22, 24, 28 Adder 20 Differentiation circuit 23 inverting circuit 25 x-direction acceleration detector 26 integral absolute value circuit 29, 30 power amplifier

Claims (1)

In the active type vibration damping actuator that attenuates the vibration by arranging the electromagnet and the magnetic body close to each other and changing the magnetic force of the electromagnet according to the vibration generated between the electromagnet and the magnetic body.
A pair of electromagnets are provided above and below, the magnetic body is disposed between the upper and lower electromagnets, and a non-magnetic conductive plate through which the lines of magnetic force of the electromagnet penetrate in a substantially vertical direction is disposed on the upper and lower surfaces of the magnetic body. A bias current of the same level is supplied to the upper and lower electromagnets, and vibrations in the height direction , that is, the z-axis direction are attenuated by increasing and decreasing the magnetic force of the upper and lower electromagnets. And generating a resistance force in a direction perpendicular to the magnetic field lines between the upper and lower electromagnets to control the displacement of the magnetic material in the x-axis direction perpendicular to the magnetic field lines of the electromagnet and in the y-axis direction perpendicular to the x-axis. Active vibration control actuator.

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